Pd Nanoparticles Encapsulated in FER Zeolite through a Layer Reassembling Strategy as Shape‐selective Hydrogenation Catalyst

Abstract

AbstractNoble metal nanoparticles (NPs) encapsulated in zeolites bearing distinct shape‐selective properties at molecular level expand their new applications in catalysis. Here we report a synthesis strategy for the encapsulation of Pd NPs inside FER zeolite via a layer reassembling process. Pd precursors were introduced by swelling FER layers in RUB‐36 through the surfactant cetyltrimethylammonium cations (CTA+) and then an ion‐exchange process at ambient temperature. Pd@FER was formed with a uniform diameter distribution of Pd NPs at about 1.4 nm during the topotactic transformation from layered zeolite precursors to 3‐dimensional zeolites followed by calcination. The as‐prepared Pd@FER catalyst exhibits distinct shape‐selective properties in hydrogenation reactions. It has relatively lower activity for 1‐hexene and almost no activity for 1‐phenyl‐1‐cyclohexene compared with Pd/RUB‐37 catalyst prepared via wet impregnation due to the restrictions of channels in the FER zeolite. On the contrary, Pd@FER shows very high hydrogenation activity for benzaldehyde and very low activity for diphenylmethanone hydrogenation, while Pd/RUB‐37 exhibits high hydrogenation activity for both benzaldehyde and diphenylmethanone. This synthesis strategy may be extended to other noble metals or two‐dimensional layered zeolite systems for size‐selective hydrogenation reactions.